Wireless short-range communication link, such as NFC or RFID may use radio frequency technology relating basically to the field of local communication technology and more particularly local communication technology involving electromagnetic and/or electrostatic coupling technology. Electromagnetic and/or electrostatic coupling is implemented in the radio frequency (RF) portion of the electromagnetic spectrum, using for example radio frequency identification (RFID) technology or near-field communication (NFC), which primarily includes radio frequency identification (RFID) transponders or near-field communication (NFC) transponders also denoted as radio frequency identification (RFID) tags or near-field communication (NFC) tags. Similarly, radio frequency identification (RFID) or near-field communication (NFC) reader interfaces for radio frequency transponders also denoted for simplicity as radio frequency identification (RFID) or near-field communication (NFC) readers.
Radio frequency identification (RFID) or near-field communication (NFC) technology is one of the recent arrivals in the terminal integration. Radio frequency identification (RFID) or near-field communication (NFC) communication enables new usage paradigms, e.g. pairing of devices, exchanging security keys, or obtaining product information by touching items provided with radio frequency identification (RFID) or near-field communication (NFC) tags with radio frequency identification (RFID) or near-field communication (NFC) communication enabled terminal. Typically, the operation range between the radio frequency identification (RFID) or near-field communication (NFC) tag and radio frequency identification (RFID) or near-field communication (NFC) reader interface in consumer applications is considered to be only a few centimeters.
There have been product releases in radio frequency identification (RFID) readers integrated in mobile apparatuses. The implementations are based on Near Field Communications (NFC) technology that operates on 13.56 MHz. The communication in that technology is obtained by inductive coupling and therefore it requires rather large coil antennas both in the reader and tag. Furthermore, inductive coupling has its limitations when it comes to the range of the radio connection.
The excitation power generated in a radio frequency identification (RFID) reader subsystem is reasonably high, from about 100 mW of consumer applications related to mobile terminal to several watts used in professional fixed applications. The used frequency allocations for UHF radio frequency identification (RFID) band are the 868 MHz ISM band in Europe and the 915 MHz band in United States. Obviously, the used frequencies are close to the used cellular frequencies, which are 880 MHz-915 MHz as well as 925 MHz-960 MHz in Europe and 824 MHz-849 MHz as well as 869 MHz-894 MHz in United States for mobile station cellular transmitter and receiver, respectively.
A local storage utilizing wireless short-range communication may be defined. Such storage concept, such as a Wireless Memory Tag (WMT), provides new environmentally friendly alternative to load especially local (but not limited to local) content from the WMT into mobile apparatuses, for example. An important differentiator to other information services is that no power consumption is required in the storage system composed by the WMT's. Only during a few second access session, some wireless power is transferred from a mobile apparatus into the WMT using Near Field Communication (NFC) power delivery capacity. The WMT may have storage capacity from 1 GB upwards, thus significantly more than in otherwise similar NFC RFID tags where there are only some kilobytes of information like URL-link address. The WMT may be independent system that does not require any cloud services but all information is comprised in the WMT's.
One of the challenges of the WMT system is to keep power consumption of a wirelessly powered memory tag, especially non-volatile memory read/write operating power, so low that the wirelessly transmitted power is enough for fast enough reading or writing content from/to the WMT. Thus, a solution is needed for an improved power consumption solution for a short-range wirelessly powered memory tag.